The older Poe's 400's were great cranks but in this day and age, the DT series is really hard to beat. The DT20 is a legit 20' bait and they're all designed by the crankbait king....David Fritts. 

But, as much as I like and use the DT's, I always have a DD22 either tied on or on deck.

The Poe's 400's are great baits, but they won't dive 20'. I usually use them down to about 16' max.

Of all the baits mentioned so far, there are only a few that will do what the poster requested, in my experience. There's a big difference between baits designed to run mid-teens and those designed to break 20'. 

Rapala DT-20

Lucky Craft CB-20

3/4 Hot Lips

Mann's 30+

I'll add the Poe's Competition Cedars 4500LR to the list of REAL 20' divers. Of all the baits listed, it gets to 20' with the least amount of resistance - - but I only use this bait for ledges.....it's pretty much a suspender and you get into cover with it, it's going to take some finesse to get it back.

The Rapala DT-20 is the best all-around 20' deep diver I've used.